package drds.server.sqlparser.sqlobject.expression.data_type;

import static drds.server.sqlparser.visitor.EvalVisitor.EVAL_VALUE_NULL;
import drds.server.sqlparser.sqlobject.expression.AbstractExpression;
import drds.server.sqlparser.visitor.Visitor;

/**
 * 
 * @author 曹正辉<330937205@qq.com>
 * 
 */
public class Null extends AbstractExpression implements DataType, Value {

	public Null() {

	}

	public void output(StringBuffer sb) {
		sb.append("null");
	}

	protected void accept0(Visitor visitor) {
		visitor.visit(this);

		visitor.endVisit(this);
	}

	public int hashCode() {
		return 0;
	}

	public boolean equals(Object o) {
		return o instanceof Null;
	}

	@Override
	public Object getValue() {
		return EVAL_VALUE_NULL;
	}
}
